| Author | Message | ||
     Hootowl |
it’s all in the valve timing. the pistons go up and down the same regardless of which direction the crank spins. | ||
| Aesquire |
Cams, ignition, and an idler gear in the transmission. Yes, They used a ( one speed ) gear reduction system to spin the props slower than the engine. Left & right hand engines had consecutive model numbers, and were used on the P-38 as well as some experimentals, like an Allison powered B-17 Escort plane that carried no bombs, but twice as many machine guns. Big fail. Loaded about the same as the Bombers ( and a bit heavier ) the Escort Fighter version didn't suddenly get lighter after passing over the target, and then couldn't keep up with the bombers, who were running away as fast & high as they could. So the heavily armed jobs found themselves the slow easy targets. Program canceled. Ironically, the Allison version was never sent to Europe, and might have had the extra power to make the failure... last a bit longer. Early P-82s used Merlins, Later models used Allisons, since the Air Force refused to pay the royalty Rolls wanted for the Packard built engines after the war, $600 each IIRC. The Designer was so upset with Allison, after they had backfire issues in the P-82 that never were resolved ( Allison folk have a different take on the subject... I have both accounts in different books ) that he kept a hatred for GM products for life. When told that he should get the New Oldsmobile with the "Automatic" transmission. he refused, saying he wasn't going have a damn GM engineer tell him when to shift. | ||
| Dwardo |
Actually the YB-40 (escort) had the same Wright engines as the normal B17. With a lot more weight, it couldn't keep up with the formation once the other bombers had dropped their bombs. There was at least one Allison-powered B17 built and it was quite strikingly pretty. | ||
| Hootowl |
“engineer tell him when to shift“ I still feel that way. Although the engineer is probably right more often. I guess it’s a control thing. | ||
| Dwardo |
That would have been the Hydramatic, which was the first true automatic transmission. I have some considerable experience with those (Hudson) and they were truly remarkable when they were new, but you would never confuse it with a modern automatic. It does a pretty good job when going up through the gears but it requires pretty much full throttle to downshift to 3rd from 4th, and it really doesn't know when to shift to 2nd. Very different. | ||
| Hootowl |
I have a th400 in my truck. | ||
| Dwardo |
No relationship except the name. The original cast iron Hydramatic was a 4-speed fully automatic that came out in 1940, I believe. It was used in some tanks in WW2 as well as automobiles. It did not have a torque converter, just a fluid coupling. I think that's why it has four gears. First is super low to make up for lack of torque multiplication. The only inputs to it are throttle position and speed. No vacuum lines, no coolant lines. They were heavily used in drag racing for a long time. But like I said, it is not really what we are used to now. | ||
| Hootowl |
Interesting, thank you. I had no idea the world had automatic transmissions as far back as the 40s. | ||
| Shoggin |
I currently have an original '60's Hydramatic 4 speed auto in my '57 Chevy behind a '66 Gen 1 275HP 327. Dwardos explanation of how they shift is spot on, lol. I'm not at all surprised they put them in TANKS! It's probably even heavier than the OG cast iron 2-speed powedrglide that came in the car stock! I learned that although they are 4-speed, they are not overdrive. High gear is still 1:1. So I'm building a TH350 with a lock-up convertor. They did that in the early 80's just before the 700R4. Fun with trannys!! oh wait  (Message edited by shoggin on August 31, 2018) | ||
| Gregtonn |
I've had a few automatic transmissions. They did their job but I never really cared for them. The shift points can be erratic especially on hills. That being said, a couple of weeks ago, I purchased a 2018 Honda CR-V with a normally aspirated 2.4l engine and CV transmission and I think I'm in love. G | ||
| Natexlh1000 |
Really agreeing with the sentiment of "engineers deciding when my car shifts" thing. I haaate Honda auto trannies. I test drove a Honda Fit with an auto. SUCKED. I bought a standard instead. Loved it. Great torquey little 1.5 engine. RUINED by garbage auto tranny. So far the only vehicles I have had with an auto that I actually liked are both Dodges. My old 1977 B200 with a 318 and my current rusting in half 2004 Ram1500. Whatever committee that Dodge has used to coach the auto tranny development is in the same mindset as me I guess. My most hated auto trannies I have had to drive: My wife's 2004 corolla. My sister's 89 honda accordion My mom's 2008 mercury marquis | ||
| Aesquire |
Love the Chrysler Torqueflites, 727-904. Loved in spades the VW dual clutch. But manual mode was making suggestions to the superior engineering staff in Wolfsburg. OTOH, sport mode was super, changing engine tune & shift points. Instant shifts, seamless power, much better than any CVT I've tried. My Caravan 6 speed is annoying,especially in eco mode. Lets it bog in the hills, and tends to double downshift when stepping harder on the gas. Suddenly you're at 4500 & screaming, when a single shift would have been appropriate. Plus each shift is a triple tone, unlock, shift, lock, so it sounds busier than it is. Can't fault the gear ratios, and manual mode is useful, but the programming is wrong. As is throttle tip in, only partly remedied in the last update I got. On the plus side, I consistently get equal or better than book mpg, and 26+ for Thruway runs, 25% better than EPA spec. It just needs a black box to diddle settings to be more drivable. | ||
| Gregtonn |
As an aside. I just was talking to a friend who said he was a life long Dodge tuck guy. He has had three auto transmissions give up on him in 2000 to 2010 trucks. All three are still sitting at his place. He isn't sure if it is electronics or valve body. I have no experience with these trucks. Any ideas? G | ||
| Fast1075 |
I had a '71 Chevelle that I transplanted a LS6 into. I killed 7 various manual shift 4 speeds in that thing. Glad my best friend owned a salvage yard! I built a TH400 using modification instructions from a Hot Rod magazine article. Full manual operation. Never broke it, not even with slicks. The only problem I had was it would chirp the tires on every shift unless you had the throttle in JUST the right position. I did have to swap in a 31 spline 9" ford rear end. The 12 bolt GM was not up to the task. (Message edited by fast1075 on September 01, 2018) | ||
| Hootowl |
I put a shift kit in mine. It’ll chirp the tires going into second. This in a truck with large tires and positraction. | ||
| Dwardo |
I have a shift kit in the 4L60E in my Roadmaster wagon. It is just enough transmission for that car with all the weight and an LT1 but it works great. Much better than my Mercury. I wish I had known you could put the torque converter from an S10 or Astro Van (whichever it was) in it for a little more stall. Well next time I break it I'll know. | ||
| Dwardo |
Shoggin is right about no overdrive. The Hudsons had about a 3.08 rear, so after driving a modern car you are always looking for another gear. It's pretty busy up there at 75mph, what with a 4 1/2 inch stroke  | ||
| Hootowl |
My truck has 4:11 gears. Not a highway cruiser, but it’ll tow just about anything. | ||
| 1313 |
Dwardo, PM sent regarding Roadmaster wagon. Please check your Email and respond. Thanks! | ||
| Dwardo |
I responded to your email. I think I did it right. If you don't get it let me know. | ||
| Ratbuell |
My Cummins tows anything, too, with 3.54 gears. And a six speed stick. I love my Dodges, but refuse to get an automatic behind a Cummins. I do love my 727s though - have had one for decades in my Satellite wagon. 400hp smallblock, full-steel car (4400+ lbs), low 13/high 12 second car. 2400 stall, reverse-manual valve body, HD bands and clutches. NEVER had a transmission failure. I will say I'm almost a fan of the new ZF 8-speed in my Grand Cherokee. I say "almost" because the Jeep engineers did a •••••• job programming the software. Mainly my issue is with downshifting during California stops - it flat out refuses to kick down. Dash will indicate third gear, I'll get halfway into the intersection, have a heart attack because cross traffic is going to hit me and I have no acceleration, and it will FINALLY kick down into second. Not first, mind you...but second. I could paddle it. I could drive around it. But for what I paid for the truck, I shouldn't have to drive around the transmission's behavior. I'll still take a 3-pedal stickshift though, any day. I do remember my '49 Coronet, and it's "Gyro-matic" clunk-o-matic 4 speed semi-auto. That was fun (read: interesting). Column shift, think 3 on the tree. Down and forward was low. Or was it up and away? I can't remember... Anyway. Give it gas. Rev it out. Lift the throttle. CLUNK. second gear. Drive through second. Clutch, shift the lever up (down?) for third. Drive through third, lift. CLUNK. Fourth gear. And I think if you were slowing, and off the throttle, it would CLUNK down 4-3 and 2-1. I think. Been years since I had it. But it was a neat survivor-gangster car, flathead six, oil-bath air cleaner and all. And BOY did that mohair interior smell tasty on a hot day!! | ||
| 1313 |
If you don't get it let me know. Didn't get it. Sent another PM last night... | ||
| Sifo |
Language warning, but some pretty wild 2 wheeled action... | ||
| Hootowl |
That looked exhausting. | ||
| Xbduck |
Gregtonn, from what I remember from the mechanic, that fixed the auto trans in my company's 2005 Dodge 3500 Cummins diesel truck, the trans doesn't run fluid through the cooler coil when the truck is idling in PARK. He said to keep the trans alive you had to put it in Neutral with the parking break on. In neutral it sends fluid through the cooler coil. This, he said, was a common problem for Dodge trucks in that decade. He also said that he learned about this because he received a notice from Dodge about his truck. That said, when it was rebuild the mechanic took care of that issue. I thought he said Dodge had a kit to repair this issue when you did a rebuild. Is it true?? I don't know, I don't know why he would lie to me about it. The cost was in line with what I expected for a rebuild. | ||
| 86129squids |
OK, thanks Tom, now I gotta go get a crowbar to pry my desk chair outta my ass. SKETCHIEST. DOWNHILL. EVAAAR. | ||
| Zac4mac |
I watched the whole 39 minutes and cannot believe that guy only fell once. Have to wonder how many times he's made that run to be that fast. Unless he has dragonfly vision and reflexes. Z | ||
| Hootowl |
He fell more than once. | ||
| Aesquire |
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| 86129squids |
There were several late video edits. I'd been splattered Spam enough to feed all the spectators. |
